This handout is for acute hf — iatrogenic hypothyroid (post-thyroidectomy / post-rai / over-treated thionamide). Your care team identified this based on: post-total or completion thyroidectomy patient presenting with new hf, fatigue, weight gain, cold intolerance, or bradycardia — replacement gap or non-adherence.
Other reasons your team may use this plan: post-rai ablation for graves disease (typically 3-12 mo prior) presenting with new hf or myxedema features — predictable iatrogenic hypothyroidism not yet replaced; patient on methimazole or ptu for hyperthyroid with rapid tsh rise and new hf symptoms — over-treatment / overshoot; tsh >50 miu/l + free t4 low + new hf or hemodynamic decompensation — primary iatrogenic hypothyroidism.
Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.
| Medication | Starting dose | How | When | What it does |
|---|---|---|---|---|
| hydrocortisone | 100 mg IV q8h until adrenal insufficiency excluded | IV | q8h | ATA 2014 PMID 25266247 + Wartofsky myxedema management — MANDATORY before thyroid replacement; 5-10% concurrent adrenal insufficiency; T4 without cortisol can precipitate adrenal crisis |
| levothyroxine | 200-500 µg IV LOAD (lower 100-200 µg if elderly/CAD/AF) then 50-100 µg IV daily until tolerating PO; PO maintenance 1.6 µg/kg IBW | IV | daily | ATA 2014 PMID 25266247 — IV loading for myxedema; oral replacement once stable; titrate to TSH 0.5-2.5 in young, 0.5-4.0 in elderly |
| liothyronine (T3) | 5-20 µg IV q8h adjunct (controversial; consider in severe myxedema coma) | IV | q8h | Wartofsky — adjunctive T3 may speed conversion in severe cases but increases cardiac risk; use cautiously in elderly/CAD |
| furosemide | 20-40 mg IV bolus (LOWER than usual due to mucinous edema not true volume + hyponatremia risk) | IV | as needed | Cautious diuresis — peripheral edema in hypothyroid is often mucinous not volume; over-diuresis worsens hyponatremia + cardiac strain; DOSE PMID 21366472 strategy adapted |
| normal saline 0.9% | 500 mL IV bolus over 30 min cautiously, then 75-100 mL/h maintenance | IV | as needed | Cautious crystalloid for hypotension; avoid free water due to hyponatremia; consider 3% saline if Na <120 with seizures |
| norepinephrine | 0.05-0.5 µg/kg/min titrate to MAP ≥65 (often poorly responsive until thyroid + cortisol replacement) | IV | continuous | SOAP-II PMID 20200382; vasopressor responsiveness improves with thyroid + cortisol replacement; may need higher than usual doses |
| atropine | 0.5-1 mg IV q3-5 min up to 3 mg | IV | as needed | AHA ACLS bradycardia algorithm; bridge to thyroid replacement / pacing |
| isoproterenol | 2-10 µg/min IV titrate | IV | continuous | Beta-1 agonist bridge for refractory bradycardia until pacing or thyroid replacement effect |
| carvedilol | 3.125 mg PO BID titrate (DEFER until euthyroid + no bradycardia) | PO | BID | GDMT for persistent HFrEF; DEFER initiation until thyroid replacement complete + bradycardia resolved (BB worsens bradycardia in active hypothyroid); CAPRICORN PMID 11356436 |
| sacubitril-valsartan | 24/26 mg PO BID titrate (DEFER until euthyroid + stable hemodynamics) | PO | BID | PIONEER-HF PMID 30403955; defer initiation until after thyroid replacement to avoid hypotension layering |
| spironolactone | 12.5-25 mg PO daily | PO | daily | RALES PMID 10471456; once euthyroid + stable |
| empagliflozin | 10 mg PO daily | PO | daily | EMPULSE PMID 35347356; once euthyroid |
Plan: Iatrogenic hypothyroid HF — STEROID FIRST then T4 replacement, cautious diuresis (mucinous edema not true volume), rate support, ADHF backbone
Contact your care team if any of the following happen:
Call 911 or go to the nearest emergency room right away if you have:
Endocrinology clinic at 2 weeks then q4-6 weeks during titration; TSH at 4-6 weeks then q3 mo once stable; cardiac follow-up for any persistent dysfunction; address iatrogenic trigger (thionamide dose adjustment, RAI follow-up replacement schedule, post-thyroidectomy lifelong replacement education); lipid management; pituitary follow-up if central hypothyroid
Guideline: ATA 2014 hypothyroidism + Klein 2007 thyroid heart NEJM + Wartofsky myxedema coma + AACE thyroid + 2022 ACC/AHA HF